1. Technical Field
The present invention relates to a liquid ejecting head, a liquid ejecting apparatus, and a piezoelectric element.
2. Related Art
As a liquid ejecting head using a piezoelectric element, for example, there is an ink jet recording head in which an oscillation plate constitutes a part of a pressure generating chamber communicating with nozzle openings which discharge ink droplets, and is deformed by a piezoelectric element to pressurize the ink in the pressure generating chamber to thereby discharge ink droplets from nozzle openings. Two types of ink jet recording heads are commercially available, and one type is an ink jet recording head using a longitudinal oscillation-mode piezoelectric actuator which is expanded or contracted in the axial direction of a piezoelectric element, and the other type is an ink jet recording head using a flexural oscillation-mode piezoelectric actuator. In such actuators, a piezoelectric element capable of obtaining large distortion with a small driving voltage, that is, a piezoelectric element having a large displacement is required for a high-density arrangement.
Therefore, as a piezoelectric material which is used for a piezoelectric layer of the piezoelectric element, for example, a metal oxide having a perovskite structure, such as lead zirconate titanate (PZT), is used (see JP-A-2001-223404 and JP-A-2008-28030).
A piezoelectric element which is provided with a piezoelectric layer made of the piezoelectric material has a high displacement, but when a high voltage is applied, dielectric breakdown may occur in some cases, and thus an improvement in voltage endurance property is required. Such a problem is present not only in liquid ejecting heads represented by ink jet recording heads, but also in other piezoelectric elements.